1. Field of the Invention
The present invention relates generally a bolt action for a firearm and more particularly to a receiver body and concomitant bolt body that facilitates the precise positioning of the bolt and firing pin within the receiver by use of forward and rear conical seating surfaces and an improved cocking piece eliminating rear bolt lift induced by angled sear engagements. The present invention further improves the ability of said receiver body to minimize undesirable vibrations during firing by producing a stronger bond between the receiver body and a firearm stock by utilizing angular spaced action screws. Furthermore, the invention provides a receiver that is superior at absorbing recoil energy with horizontally in line recoil lug surfaces.
2. Description of the Related Art
A wide variety of bolt actions for firearms have been practiced since the invention of the bolt action rifle. Prior art bolt actions have as one paramount object the precise perpendicularity of a bolt face to a cartridge chamber, thereby properly positioning a firing pin carried and actuated by the action to strike the primer of a cartridge. Furthermore, by providing precise positioning of the bolt, pressure by the firing pin spring is uniformly dispersed to front locking lugs of the bolt. To provide for precise and repeatable results in firing, it is desirable to secure proper positioning of the bolt in its proper position, relatively immovable with respect to the cartridge and barrel of the firearm during firing pin movement and striking of the cartridge primer.
Due to the inherent nature of modern high-powered rifles the bolt mechanism is subjected to enormous stress under firing conditions as the gas pressure caused by a cartridge firing builds rapidly and expels a projectile from the barrel. Furthermore, in order to achieve precise accuracy during firing it is essentially that the axis of the bolt, and thus the axis of the firing pin, be concentric with the axis of the bore of a firearm barrel, also thereby providing a perpendicular surface to accept a cartridge head. In order to repeat this accurate performance the concentricity of these components must be repeatable each time the bolt is closed.
Many prior art actions utilize sear override trigger systems, which have an inherent flaw where bolt concentricity is concerned. The angled face of the sear contacts the cocking piece face, causing the cocking piece to ride up the sear face when under pressure from the firing pin spring. This in turn forces the rear of the bolt to rise and the top locking lugs at the front of the bolt to be forced slightly forward, which of course prevents proper alignment of the bolt within the action. Generally speaking, the spring pressure at the bottom of the bolt forces unequal pressure of the locking lugs in their seats, thus preventing precise concentric alignment of the bolt and consistent front locking lug pressure.
Additionally, modern rifle target shooters “tune” their rifles to minimize the effect of accuracy-robbing vibrations. These vibrations occur in part from bolt movement once the firing pin spring is actuated, since for most prior art actions at that point the rear of the bolt is capable of some movement with respect to the action. Thus some harmonic vibrations can be attributed to the play between the bolt and the receiver, thereby decreasing accuracy of the firearm.
Producing the correct union between the receiver body and the firearm stock is one method to obviate undesirable vibrations and prevent potential movement of the receiver body in the firearm stock. Prior art bolt actions utilize two to three action screws to secure the receiver body (with attached barrel) to the firearm stock. To aid barrel accuracy, modern rifle target shooters will “float” the barrel, thus eliminating any contact between the barrel and the firearm stock. Thus the full weight of the receiver body and barrel is applied to the joining surfaces of the receiver body in the firearm stock, fastened in place by the aforementioned action screws. To strengthen this union, thereby minimizing vibrations and preventing the receiver body from shifting inside the firearm stock, epoxy based “bedding” is used. In some instances in order to maximize results the bedding process permanently attaches the receiver to the firearm stock.
Additionally, many prior art bolt actions utilize a recoil lug positioned proximate the lowest or bottom-most point of the receiver body to absorb recoil energy generated during firing. Locating recoil lug surfaces only at the very bottom of the receiver body allows recoil energy generated at the barrel's bore to be transferred in an upwards direction, applying additional stress on the union of the receiver body and firearm stock and creating additional harmonic vibrations.
Another accepted technique for maximizing accuracy is the use of small firing pin tips, which tend to yield better ignition while minimizing spring pressure required to actuate the pin. Reduced spring pressure facilitates easy bolt lift and closure and creates reduced vibration as well. However, tight tolerances required for a conventional single-piece firing pin riding inside the bolt body can be difficult and costly to produce. Additionally, the problem of rear bolt lift, particularly caused by angled sear surfaces, can cause the firing pin to flex or bind as it is forced forward during firing, inducing bending or even breaking smaller diameter tips. Some prior art bolt actions utilize floating firing pin tips which allow inadvertent contact with the cartridge primer before actual discharge of the firearm and can allow metal to metal impact during discharging the firearm, creating the possibility of additional undesirable vibrations.
Accordingly, a need exists for a bolt action for a firearm that minimizes or eliminates the aforementioned problems while providing for consistent, reproducible, and accurate firing under all conditions.